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Battery Discharging

2387 Views 9 Replies 3 Participants Last post by  retro
I have been troubleshooting my fathers 1999 Honda TRX450R four wheeler for the last 2 days, but am confused:
Battery would go dead about every 4 days if you did not ride it, tested the battery and replaced it because it had a dead cell.
Four days later the new battery was dead.

Started to troubleshoot it yesterday using the troubleshooting procedures in the shop manual.
- Charged battery for 8 hours, meter reading was 13.1 volts. Tried to start it and the starter relay clicks but the started does not turn over.
- It starts on the first pull and idles normally.
- Conducted the “Current Leakage Inspection”, the current leakage was off the scale (my meter only reads to 20 Ma), so I assumed I had a short. I looked at all of the cables and could not find
a short. Pulled all of the fuses and still reads over 20 Ma.
- Disconnected the regulator/rectifier and conducted the “Current leakage test” again same result.
- I could not figure out how to test the ignition switch, but is seem to be working correctly. When turned to run the Neutral Indicator, Speedo, and hours show on the screen; and when you
turn the switch to off everything goes out.
- When changing the meter to DC Voltage I noticed that I am getting 11.2 volts DC when the meter is connected between the battery negative terminal and the Negative cable, the key was off
so I still assumed I had a short somewhere.
- I conducted the “Alternator Charging Coil” test and everything passed (.6 ohm on the stator coils) so I assume the stator is not the cause of a short.
- I disconnected the Regulator/Rectifier, and all three of the connections on the frame one at a time and I continued to have 11.2 volts on the meter between the negative cable and battery
- I pulled all four of the fuses one at a time and still had 11.2 volts.
- All of the above tests were with the ignition switch off, so I should not have had any voltage on the ground.
- I then tested from the negative terminal on the battery to the starter lug and had 10.7 volts, with the ignition switch off so it still seems like a short but I cannot figure out where the short
would be coming from. So I disconnected the power lead from the starter and test again, still 10.7 volts so the voltage must be coming through the ground system somewhere.

Any ideas on what to check next would be appreciated, at this point I am lost.

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Disconnect the solenoid and see if that solves the drain. Also loosen and clean the frame ground for the wiring harness and do the same for the negative cable motor ground. Let us know how it goes if you can and welcome to the forums!

EDIT: While the solenoid is disconnected check it with an ohms meter if ya got one, see if it is shorted. Also look up the starting section in the manual and do continuity tests on every component that you see on the diagram at the beginning of that section.
Yeah, it looks like the regulator/rectifier is bad. Great work diagnosing it by the way...! :)

You mentioned that the three charging coil resistance tests passed. Did you test between each of the three charging coil wires and ground? There should be no continuity to ground with each.

I am not familiar with that model so I'm guessing... is the frame ground for the wiring harness near the CDI?
Does it crank over with the starter now? You didn't mention anything about that...
Does it crank over with the starter now? You didn't mention anything about that...
Great, let us know how it goes if you can!
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